lnd.xprv/channeldb/db.go
2017-03-13 16:30:23 -07:00

468 lines
12 KiB
Go

package channeldb
import (
"bytes"
"encoding/binary"
"fmt"
"os"
"path/filepath"
"sync"
"github.com/boltdb/bolt"
"github.com/roasbeef/btcd/btcec"
"github.com/roasbeef/btcd/wire"
)
const (
dbName = "channel.db"
dbFilePermission = 0600
)
// migration is a function which takes a prior outdated version of the database
// instances and mutates the key/bucket structure to arrive at a more
// up-to-date version of the database.
type migration func(tx *bolt.Tx) error
type version struct {
number uint32
migration migration
}
var (
// dbVersions is storing all versions of database. If current version
// of database don't match with latest version this list will be used
// for retrieving all migration function that are need to apply to the
// current db.
dbVersions = []version{
{
// The base DB version requires no migration.
number: 0,
migration: nil,
},
{
number: 1,
migration: deliveryScriptBugMigration,
},
}
// Big endian is the preferred byte order, due to cursor scans over
// integer keys iterating in order.
byteOrder = binary.BigEndian
)
var bufPool = &sync.Pool{
New: func() interface{} { return new(bytes.Buffer) },
}
// DB is the primary datastore for the lnd daemon. The database stores
// information related to nodes, routing data, open/closed channels, fee
// schedules, and reputation data.
type DB struct {
*bolt.DB
dbPath string
}
// Open opens an existing channeldb. Any necessary schemas migrations due to
// updates will take place as necessary.
func Open(dbPath string) (*DB, error) {
path := filepath.Join(dbPath, dbName)
if !fileExists(path) {
if err := createChannelDB(dbPath); err != nil {
return nil, err
}
}
bdb, err := bolt.Open(path, dbFilePermission, nil)
if err != nil {
return nil, err
}
chanDB := &DB{
DB: bdb,
dbPath: dbPath,
}
// Synchronize the version of database and apply migrations if needed.
if err := chanDB.syncVersions(dbVersions); err != nil {
bdb.Close()
return nil, err
}
return chanDB, nil
}
// Wipe completely deletes all saved state within all used buckets within the
// database. The deletion is done in a single transaction, therefore this
// operation is fully atomic.
func (d *DB) Wipe() error {
return d.Update(func(tx *bolt.Tx) error {
err := tx.DeleteBucket(openChannelBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(closedChannelBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(invoiceBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(nodeInfoBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(nodeBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(edgeBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(edgeIndexBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
err = tx.DeleteBucket(graphMetaBucket)
if err != nil && err != bolt.ErrBucketNotFound {
return err
}
return nil
})
}
// createChannelDB creates and initializes a fresh version of channeldb. In
// the case that the target path has not yet been created or doesn't yet exist,
// then the path is created. Additionally, all required top-level buckets used
// within the database are created.
func createChannelDB(dbPath string) error {
if !fileExists(dbPath) {
if err := os.MkdirAll(dbPath, 0700); err != nil {
return err
}
}
path := filepath.Join(dbPath, dbName)
bdb, err := bolt.Open(path, dbFilePermission, nil)
if err != nil {
return err
}
err = bdb.Update(func(tx *bolt.Tx) error {
if _, err := tx.CreateBucket(openChannelBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(closedChannelBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(invoiceBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(nodeInfoBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(nodeBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(edgeBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(edgeIndexBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(graphMetaBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(metaBucket); err != nil {
return err
}
meta := &Meta{
DbVersionNumber: getLatestDBVersion(dbVersions),
}
return putMeta(meta, tx)
})
if err != nil {
return fmt.Errorf("unable to create new channeldb")
}
return bdb.Close()
}
// fileExists returns true if the file exists, and false otherwise.
func fileExists(path string) bool {
if _, err := os.Stat(path); err != nil {
if os.IsNotExist(err) {
return false
}
}
return true
}
// FetchOpenChannels returns all stored currently active/open channels
// associated with the target nodeID. In the case that no active channels are
// known to have been created with this node, then a zero-length slice is
// returned.
func (d *DB) FetchOpenChannels(nodeID *btcec.PublicKey) ([]*OpenChannel, error) {
var channels []*OpenChannel
err := d.View(func(tx *bolt.Tx) error {
// Get the bucket dedicated to storing the metadata for open
// channels.
openChanBucket := tx.Bucket(openChannelBucket)
if openChanBucket == nil {
return nil
}
// Within this top level bucket, fetch the bucket dedicated to storing
// open channel data specific to the remote node.
pub := nodeID.SerializeCompressed()
nodeChanBucket := openChanBucket.Bucket(pub)
if nodeChanBucket == nil {
return nil
}
// Finally, we both of the necessary buckets retrieved, fetch
// all the active channels related to this node.
nodeChannels, err := d.fetchNodeChannels(openChanBucket,
nodeChanBucket)
if err != nil {
return fmt.Errorf("unable to read channel for "+
"node_key=%x: %v", pub, err)
}
channels = nodeChannels
return nil
})
return channels, err
}
// fetchNodeChannels retrieves all active channels from the target
// nodeChanBucket. This function is typically used to fetch all the active
// channels related to a particualr node.
func (d *DB) fetchNodeChannels(openChanBucket,
nodeChanBucket *bolt.Bucket) ([]*OpenChannel, error) {
var channels []*OpenChannel
// Once we have the node's channel bucket, iterate through each
// item in the inner chan ID bucket. This bucket acts as an
// index for all channels we currently have open with this node.
nodeChanIDBucket := nodeChanBucket.Bucket(chanIDBucket[:])
if nodeChanIDBucket == nil {
return nil, nil
}
err := nodeChanIDBucket.ForEach(func(k, v []byte) error {
if k == nil {
return nil
}
outBytes := bytes.NewReader(k)
chanID := &wire.OutPoint{}
if err := readOutpoint(outBytes, chanID); err != nil {
return err
}
oChannel, err := fetchOpenChannel(openChanBucket,
nodeChanBucket, chanID)
if err != nil {
return fmt.Errorf("unable to read channel data for "+
"chan_point=%v: %v", chanID, err)
}
oChannel.Db = d
channels = append(channels, oChannel)
return nil
})
if err != nil {
return nil, err
}
return channels, nil
}
// FetchAllChannels attempts to retrieve all open channels currently stored
// within the database.
func (d *DB) FetchAllChannels() ([]*OpenChannel, error) {
return fetchChannels(d, false)
}
// FetchPendingChannels will return channels that have completed the process
// of generating and broadcasting funding transactions, but whose funding
// transactions have yet to be confirmed on the blockchain.
func (d *DB) FetchPendingChannels() ([]*OpenChannel, error) {
return fetchChannels(d, true)
}
// fetchChannels attempts to retrieve channels currently stored in the
// database. The pendingOnly parameter determines whether only pending
// channels will be returned. If no active channels exist within the network,
// then ErrNoActiveChannels is returned.
func fetchChannels(d *DB, pendingOnly bool) ([]*OpenChannel, error) {
var channels []*OpenChannel
err := d.View(func(tx *bolt.Tx) error {
// Get the bucket dedicated to storing the metadata for open
// channels.
openChanBucket := tx.Bucket(openChannelBucket)
if openChanBucket == nil {
return ErrNoActiveChannels
}
// Next, fetch the bucket dedicated to storing metadata
// related to all nodes. All keys within this bucket are the
// serialized public keys of all our direct counterparties.
nodeMetaBucket := tx.Bucket(nodeInfoBucket)
if nodeMetaBucket == nil {
return fmt.Errorf("node bucket not created")
}
// Finally for each node public key in the bucket, fetch all
// the channels related to this particualr ndoe.
return nodeMetaBucket.ForEach(func(k, v []byte) error {
nodeChanBucket := openChanBucket.Bucket(k)
if nodeChanBucket == nil {
return nil
}
nodeChannels, err := d.fetchNodeChannels(openChanBucket,
nodeChanBucket)
if err != nil {
return fmt.Errorf("unable to read channel for "+
"node_key=%x: %v", k, err)
}
if pendingOnly {
for _, channel := range nodeChannels {
if channel.IsPending == true {
channels = append(channels, channel)
}
}
} else {
channels = append(channels, nodeChannels...)
}
return nil
})
})
return channels, err
}
// MarkChannelAsOpen records the finalization of the funding process and marks
// a channel as available for use.
func (d *DB) MarkChannelAsOpen(outpoint *wire.OutPoint) error {
err := d.Update(func(tx *bolt.Tx) error {
openChanBucket := tx.Bucket(openChannelBucket)
if openChanBucket == nil {
return ErrNoActiveChannels
}
// Generate the database key, which will consist of the IsPending
// prefix followed by the channel's outpoint.
var b bytes.Buffer
if err := writeOutpoint(&b, outpoint); err != nil {
return err
}
keyPrefix := make([]byte, 3+b.Len())
copy(keyPrefix[3:], b.Bytes())
copy(keyPrefix[:3], isPendingPrefix)
// For the database value, store a zero, since the channel is no
// longer pending.
scratch := make([]byte, 2)
byteOrder.PutUint16(scratch, uint16(0))
return openChanBucket.Put(keyPrefix, scratch)
})
if err != nil {
return err
}
return nil
}
// syncVersions function is used for safe db version synchronization. It applies
// migration functions to the current database and recovers the previous
// state of db if at least one error/panic appeared during migration.
func (d *DB) syncVersions(versions []version) error {
meta, err := d.FetchMeta(nil)
if err != nil {
if err == ErrMetaNotFound {
meta = &Meta{}
} else {
return err
}
}
// If the current database version matches the latest version number,
// then we don't need to perform any migrations.
latestVersion := getLatestDBVersion(versions)
log.Infof("Checking for schema update: latest_version=%v, "+
"db_version=%v", latestVersion, meta.DbVersionNumber)
if meta.DbVersionNumber == latestVersion {
return nil
}
log.Infof("Performing database schema migration")
// Otherwise, we fetch the migrations which need to applied, and
// execute them serially within a single database transaction to ensure
// the migration is atomic.
migrations, migrationVersions := getMigrationsToApply(versions,
meta.DbVersionNumber)
return d.Update(func(tx *bolt.Tx) error {
for i, migration := range migrations {
if migration == nil {
continue
}
log.Infof("Applying migration #%v", migrationVersions[i])
if err := migration(tx); err != nil {
log.Infof("Unable to apply migration #%v",
migrationVersions[i])
return err
}
}
meta.DbVersionNumber = latestVersion
return putMeta(meta, tx)
})
}
// ChannelGraph returns a new instance of the directed channel graph.
func (d *DB) ChannelGraph() *ChannelGraph {
return &ChannelGraph{d}
}
func getLatestDBVersion(versions []version) uint32 {
return versions[len(versions)-1].number
}
// getMigrationsToApply retrieves the migration function that should be
// applied to the database.
func getMigrationsToApply(versions []version, version uint32) ([]migration, []uint32) {
migrations := make([]migration, 0, len(versions))
migrationVersions := make([]uint32, 0, len(versions))
for _, v := range versions {
if v.number > version {
migrations = append(migrations, v.migration)
migrationVersions = append(migrationVersions, v.number)
}
}
return migrations, migrationVersions
}